MIMO OFDM Beamforming for QoS Enhancement in Integrated Broadband Multi-User Communication and Beampattern Synthesis

This paper addresses beamforming design for broadband integrated sensing and communication systems that simultaneously serve multiple communication users (CUs) and sense multiple targets. In this setting, a base station transmits multi-stream information to CUs equipped with multiple antennas over frequency-selective MIMO OFDM channels, while probing the environment using multibeam waveforms. We formulate new beamforming design problems that balance three competing objectives: the sum-rate of CUs, fairness in CU rates (min-rate), and the directional selectivity of the multibeam beampattern, subject to a transmit power constraint. To solve these problems efficiently, we develop computationally tractable path-following algorithms that rely on closed-form updates. Numerical experiments show that the proposed designs significantly outperform existing methods in both communication performance and beampattern quality. These results highlight the practical potential of our approach for wireless systems that demand both high data rates and accurate environmental awareness.